Halowerk MCP runs on your own machine — the client starts it, so there is no endpoint to ping. 58 installs a week from npm. Last commit 12 Aug 2026.
134 paid APIs as MCP tools, billed per call in USDC on Base. No account, no login.
Today is the operative word: we check Halowerk MCP every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add halowerk-mcp -- npx -y halowerk-mcp
{
"mcpServers": {
"halowerk-mcp": {
"args": [
"-y",
"halowerk-mcp"
],
"command": "npx"
}
}
}
[mcp_servers.halowerk-mcp]
command = "npx"
args = ["-y", "halowerk-mcp"]
{
"mcpServers": {
"halowerk-mcp": {
"args": [
"-y",
"halowerk-mcp"
],
"command": "npx"
}
}
}
{
"mcpServers": {
"halowerk-mcp": {
"args": [
"-y",
"halowerk-mcp"
],
"command": "npx"
}
}
}
This one needs environment variables set before it will start:
HALOWERK_PRIVATE_KEY (Private key of the paying wallet, hex with or without 0x. Use a throwaway wallet holding only a few dollars of USDC on Base. Without it, only the free catalogue and price tools work.), HALOWERK_MAX_PREIS_USDC (Ceiling per call in USDC. A more expensive service is refused, not bought. Default 0.05.), HALOWERK_BUDGET_USDC (Ceiling per session in USDC. Once reached the server refuses further paid calls. Default 1.00.), HALOWERK_MODUS (hero (12 curated services, default), gateway (3 meta-tools, smallest context) or all (70 services).), HALOWERK_TROCKEN (Set to 1 for a dry run: returns price and call plan, pays nothing.).
The author declared them in the registry entry; get the values from the project itself.
PathCourse Health inference SKUs as x402 paid MCP tools, billed per call in USDC on Base.
melis x402 Tools — 22 pay-per-call APIs for AI agents. No accounts, no API keys. USDC on Base.
Ethereum mainnet JSON-RPC paid per call in USDC on Base. No account, no API key: the wallet pays.
x402 pay-per-call: 146 MCP tools, no account or key. USDC on Base + Solana, $0.001-$0.01/call.
11 pay-per-call web tools for AI agents, auto-paid in USDC on Base via x402. No API keys.
Otto AI hosted MCP: 16 pay-per-call market-intelligence tools, USDC via x402 on Base, no API keys.
Pay-per-call agent tools over x402 (USDC on Base) — no signup or API key.
Pay-per-call agent tools via x402 (USDC on Base): chat, prices, funding, RNG. No account or keys.
Answers built from our own checks of this server.